Merge branch 'for-3.12/core' of git://git.kernel.dk/linux-block

Pull block IO fixes from Jens Axboe:
 "After merge window, no new stuff this time only a collection of neatly
  confined and simple fixes"

* 'for-3.12/core' of git://git.kernel.dk/linux-block:
  cfq: explicitly use 64bit divide operation for 64bit arguments
  block: Add nr_bios to block_rq_remap tracepoint
  If the queue is dying then we only call the rq->end_io callout. This leaves bios setup on the request, because the caller assumes when the blk_execute_rq_nowait/blk_execute_rq call has completed that the rq->bios have been cleaned up.
  bio-integrity: Fix use of bs->bio_integrity_pool after free
  blkcg: relocate root_blkg setting and clearing
  block: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...)
  block: trace all devices plug operation

1 files changed, 15 insertions, 10 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index e90c7c164c83..4e491d9b5292 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -235,8 +235,13 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
         blkg->online = true;
         spin_unlock(&blkcg->lock);
 
-        if (!ret)
+        if (!ret) {
+                if (blkcg == &blkcg_root) {
+                        q->root_blkg = blkg;
+                        q->root_rl.blkg = blkg;
+                }
                 return blkg;
+        }
 
         /* @blkg failed fully initialized, use the usual release path */
         blkg_put(blkg);
@@ -335,6 +340,15 @@ static void blkg_destroy(struct blkcg_gq *blkg)
                 rcu_assign_pointer(blkcg->blkg_hint, NULL);
 
         /*
+         * If root blkg is destroyed.  Just clear the pointer since root_rl
+         * does not take reference on root blkg.
+         */
+        if (blkcg == &blkcg_root) {
+                blkg->q->root_blkg = NULL;
+                blkg->q->root_rl.blkg = NULL;
+        }
+
+        /*
          * Put the reference taken at the time of creation so that when all
          * queues are gone, group can be destroyed.
          */
@@ -360,13 +374,6 @@ static void blkg_destroy_all(struct request_queue *q)
                 blkg_destroy(blkg);
                 spin_unlock(&blkcg->lock);
         }
-
-        /*
-         * root blkg is destroyed.  Just clear the pointer since
-         * root_rl does not take reference on root blkg.
-         */
-        q->root_blkg = NULL;
-        q->root_rl.blkg = NULL;
 }
 
 /*
@@ -970,8 +977,6 @@ int blkcg_activate_policy(struct request_queue *q,
                 ret = PTR_ERR(blkg);
                 goto out_unlock;
         }
-        q->root_blkg = blkg;
-        q->root_rl.blkg = blkg;
 
         list_for_each_entry(blkg, &q->blkg_list, q_node)
                 cnt++;